The Camshaft/valve is made up of components including this Cam Shaft Exh which is the most expensive.
Some items from this specific schematic: Valve,exhaust, Nut Tappet Adjg, Spg,valve Outer, Guide,rocker Arm.
The most reasonably priced component used on the Cbr600f Hurricane 1990 (l) Italy / Kph Camshaft/valve is the Nut Tappet Adjg.